Cytomorphological spectrum of lymphocytic thyroiditis: correlation with thyroid hormones and antibodies in a South Delhi Tertiary Care Center

Background: Lymphocytic thyroiditis, also known as Hashimoto’s thyroiditis (HT), is a chronic autoimmune condition characterized by the immune-mediated destruction of thyroid tissue. The disease arises from a combination of genetic predisposition, environmental triggers, and immune system dysfunction. Clinically, it often presents as a painless thyroid enlargement or with signs of hypothyroidism. Fine-needle aspiration cytology (FNAC) is a widely utilized, minimally invasive method for diagnosing HT. Objective: This study aimed to categorize lymphocytic thyroiditis based on detailed cytomorphological characteristics identified through FNAC and to assess the correlation between cytological grading, anti-thyroid peroxidase (ATPO) antibody levels, and thyroid hormone profiles. The goal was to understand disease progression better and improve diagnostic accuracy. Materials and Methods: A pilot study was conducted at the Hamdard Institute of Medical Sciences and Research, along with Hakeem Abdul Hameed Centenary Hospital, New Delhi. Thirty-eight patients (aged 18–62 years) with thyroid swellings and diagnosed with HT based on FNAC findings and/or elevated ATPO levels were included. Cytological grading was carried out, and corresponding thyroid function tests and ATPO antibody levels were analyzed. Results: Cytological grading via FNAC showed Grade I in 60.5% (23 cases), Grade II in 23.6% (nine cases), and Grade III in 15.9% (six cases). Thyroid function tests revealed hypothyroidism in 50% (19 cases), euthyroidism in 31.6% (12 cases), and hyperthyroidism in 18.4% (seven cases). Most hypothyroid cases were classified as Grade I. Elevated ATPO antibody levels were found in 73.7% (28/38) of patients. All cases classified as Grade II and III showed ATPO positivity, while 56.5% of Grade I cases had elevated antibodies. A statistically significant correlation was observed between cytological grade and ATPO levels ( P = 0.011). Conclusion: FNAC is a reliable and effective diagnostic method for evaluating and grading lymphocytic thyroiditis. The significant correlation between cytological grade, ATPO antibody levels, and thyroid hormone status underscores the need for a multidisciplinary diagnostic approach. This integration aids in more accurate disease assessment, effective monitoring, and personalized management of patients with HT.